Epicodakia Iredale, 1930

Glover, Emily A. & Taylor, John D., 2007, Diversity of chemosymbiotic bivalves on coral reefs: Lucinidae (Mollusca, Bivalvia) of New Caledonia and Lifou, Zoosystema 29 (1), pp. 109-181 : 136-137

Genus Epicodakia Iredale, 1930

Epicodakia Iredale,1930: 390 . Type species: Epicodakia consettiana Iredale, 1930 (earlier name Lucina minima Tenison-Woods, 1876 , preoccupied by L. minima Roemer, 1836 ) (original designation).

Talocodakia Iredale, 1936: 273 . Type species: Talocodakia kennethi Iredale, 1936 (original designation).

DIAGNOSIS. — Shells small to medium sized, longer than high, regularly ovate in outline with low umbones. Sculpture of 20 to 75 regularly spaced, narrow or broad radial ribs, rarely bifurcating, crossed by commarginal lamellae producing low, rounded, often closely-spaced scales on summits of ribs, (basketwork or snakeskin effect). Ligament external, short. Hinge plate narrow; 2 cardinal teeth in each valve, the larger usually bifurcate, with single anterior and posterior lateral teeth in RV and paired in LV. Anterior adductor scars medium long, detached for about 1/2 of length. Shell margin smooth or finely denticulate.

REMARKS

There has been much confusion concerning use of this generic name, especially since Iredale (1930) included E. gunnamatta Iredale, 1930 (a Ctena species ) within his concept of the genus. Furthermore, Chavan (1969: fig. E3.9b) figured Ctena divergens as an example of Epicodakia and provided only a small, poorly reproduced image (fig. E2.2) of the outside of E. consettiana . Also, the various southern Australian species that have been included within Epicodakia appear to be a heterogeneous group of lucinids. In order to clarify the concept of Epicodakia , we include here a description and illustrations of the type species.

The type species, E. consettiana , has less prominent sculpture, with a larger number of radial ribs than some of the other species we have included in the genus, but other features including overall shell shape, ligament, hinge teeth and muscle scars are similar.

Ctena species can be distinguished from Epicodakia by their more circular outline, the strong, bifurcating and intercalating radial ribs and the short ligament that is deeply inset into hinge plate.

We include the following IWP species in our concept of Epicodakia : Lucina obliqua Reeve, 1850 , China; E. sweeti ( Hedley, 1899) see below; E.nodulosa n. sp.; Lucina minuata Deshayes, 1863 , Réunion; E. neozelanica Powell, 1937 , New Zealand. The southern Atlantic species Epicodakia falkandica Dell, 1964 has little resemblance to the type species and should be excluded from the genus.